Industrial wastewater from plants is subjected to purifying treatment, such as elimination of heavy metal components, suspended particles, and the like and decomposition and elimination of organic matter by microorganisms. Although the treated water subjected to the purifying treatment is generally discharged into the environment, the treated water obtained by subjecting the industrial wastewater to the purifying treatment is reused for industrial water in places where it is difficult to secure industrial water. In this case, as described in PTL 1, the desalination treatment of eliminating ionic components contained in the wastewater is performed after the heavy metal components, the suspended particles, the organic matter, and the like are eliminated.
In a wastewater treatment device of PTL 1, an electrodialysis method, a reverse osmotic method, and an ion-exchange resin method are applied as the desalination treatment. In the electrodialysis method, the ionic components in the wastewater are eliminated using energization and an ion exchange membrane. In the reverse osmotic method, the ionic components in the wastewater are eliminated using a reverse osmosis membrane. Additionally, in the ion-exchange resin method, the ionic components in the wastewater are eliminated using an ion exchange resin.